How HIV Affects the Immune System

Human immunodeficiency virus (HIV) is a retrovirus that gradually destroys the immune system. It disables and kills CD4+ T cells. With fewer CD4+ T cells the immune system has a more difficult time fighting infection. Concentrated levels of CD4+ T cells trigger other immune system cells to attack invading organisms. If CD4+ T cell levels are destroyed the other immune system cells will not be triggered and infection will persist and grow.

A healthy person has between 800 and 1200 CD4+ T cells per cubic millimeter of blood. A person with HIV will have only 200 CD4+ T cells per millimeter of blood. This is equal to or less than 14% of the total number in a health person. This is way people with HIV are more susceptible to infections and cancers.

There are three ways HIV is transmitted. Injection of infected blood or blood products, sexual contact, and maternal-fetal transmissions are the only ways this virus is transmitted.

Three enzymes, reverse transcriptase, integrase, and protease are used by the HI virus to genetically code, replicate and assemble new HI virus in a host cell. HIV can only replicate inside host cells. This is one reason why HIV can not survive long out side of the host environment.

The FDA has approved four classes of medication for treatment of HIV. These are:

Nonnucleoside Reverse Transcriptase Inhibitors (NNRTIs)

This class of medication binds to reverse transcriptase. By binding with reverse transcriptase the HI virus does not have the opportunity to bind disabling the virus ability to uncoat and convert into DNA.

Necueoside Reverse Transcriptase Inhibitors (NRTIs)

NRTIs are faulty version reverse transcriptase. The HI virus can not tell the difference between actual reverse transcriptase and a NRTI this stalls the reproduction of HIV and slows down the growth of the virus in the body.

Protease Inhibitors

HIV can not make copies of itself with out the protein, protease. Protease inhibitors disable protease from bonding with HIV.

Fusion Inhibitors

Fusion inhibitors are effective at preventing HIV from entering into the CD4+ T cells.